Project 1 - Parsing NASA thermodynamic data

AIM : To obtain NASA thermodynamic data for various species,coefficients of temperature and to find specific-heat,enthalpy and entropy using MATLAB code.

INPUTS USED :

• R = 8.31446261815324 (Universal gas constant)
• Given THERMO.txt file

A detailed report to describe my logic.

1. Using thermodynamic data opening the file contents in editor window.
2. Calling the command 'fgetl' to read out each line of the THERMO.txt file and naming as 'tlines' where it can save.
3. Converting my string to number to perform ease way of calculations for each tline operation.
4. Using formula given calculations for enthalpy, entropy and specific heat of low to high temperatures are done.
5. Calling my function to run the code to calculate molecular weight as well as atomic weight for every species mentioned.
6. Making plots for each and every species .
7. Defined my file directory where to save.
8. finally when is code excicuted required data is printed.

FORMULA :

PARSING DATA:

• Parsing means to make something understandable. For programming this means to convert information represented in one form into another form that's easier to work with. This is done by partially analysing the data, understanding its underlying structure (by making some assumptions based on what you're expecting to see), and then explicitly representing that structure in the code.
• Parsing a file means reading in a data stream of some sort and building an in memory model of the semantic content of that data. This aims at facilitating perfoming some kind of transformation on the data.

EQUATIONS:

The equations that we are going to use in the Functions to calculate cp, H,S are:

cpR=a1+a2T+a3T2+a4T3+a5T4">cpR=a1+a2T+a3T2+a4T3+a5T4cpR=a1+a2T+a3T2+a4T3+a5T4

HRT=a1+a2T2+a3T23+a4T34+a5T45+a6T">HRT=a1+a2T2+a3T23+a4T34+a5T45+a6THRT=a1+a2T2+a3T23+a4T34+a5T45+a6T

SR=a1lnT+a2T+a3T22+a4T33+a5T44+a7">SR=a1lnT+a2T+a3T22+a4T33+a5T44+a7SR=a1lnT+a2T+a3T22+a4T33+a5T44+a7

Where,

Cp=specific heat

R =molar gas constant

T=temperature

S=Entropy

H=Enthalpy

a=coefficients

%clear all the previous data or stores values
clear all
close all
clc

%Open the the THERMO.dat file
f1=fopen('THERMO.dat','r')

%skip the first line of the file
fgetl(f1);

%reading the tempersture values distingushed as local,average and high temperatures
line=fgetl(f1);
a=strsplit(line,' ');
global_low_temp=str2num(a{2});
global_average_temp=str2num(a{3});
global_high_temp=str2num(a{4});
fgetl(f1);
fgetl(f1);
fgetl(f1);

%extracting data for each gas
for k=1:53
    
    %step7
    line=fgetl(f1);
    a=strsplit(line,' ');
    Gas=a(1);
    b=findstr(line,'.');
    local_low_temp=str2num(line(b(1)-4:b(1)+4));
    local_high_temp=str2num(line(b(2)-4:b(2)+4));
    local_average_temp=str2num(line(b(3)-4:b(3)+4));
    
    %extracting all 14 coefficients
    ct=1;
    for j=1:3
        line=fgetl(f1);
        b=strfind(line,'E');
        for i=1:length(b)
            if ct<=7
                Ha(ct)=str2num(line(b(i)-11:b(i)+3));
                ct=ct+1;
            else
              La(ct-7)=str2num(line(b(i)-11:b(i)+3));
              ct=ct+1;
            
            end
        end
    end
    
    %initializing specific heat,entropy and enthalpy values to zero
    cp=0;
    H=0;
    S=0;
    
    %calling the function where cp,H and S are calculated
    [Cp,H,S] = coefficient(local_low_temp,local_average_temp,local_high_temp,La,Ha);
    
    %molecular weight calculating function
    M=Weight(Gas)
    
    %plotting
    GAS=char(Gas);
    T=local_low_temp:local_high_temp;
    current=pwd;
    mkdir(GAS);
    cd(GAS)
    figure(1);
    plot(T,Cp,'color','g','linewidth',2);
    legend(Gas);
    txt1=['Molecular weight:' num2str(M)];
    text(500,max(Cp)*0.98,txt1,'color','r');
    grid on
    
    xlabel('temperature(K)');
    ylabel('Specific heat(KJ/mol)');
    title('specific heat vs temperrature');
    
    figure(2);
    plot(T,H,'color','r','linewidth',2);
    legend(Gas);
    txt1=['molecular weight:' num2str(M)];
    text(500,max(H)*0.98,txt1,'color','b');
    grid on
    xlabel('temperrature(K)');
    ylabel('enthalpy(kj/mol)');
    title('enthalpy vs temperature');
    
    figure(3);
    plot(T,S,'color','b','linewidth',2);
    legend(Gas);
    txt1=['Molecular weight:' num2str(M)];
    text(500,max(S)*0.98,txt1,'color','b');
    grid on
    xlabel('temperature(K)');
    ylabel('entropy (KJ/mol)');
    title('entropy vs temperature');
    
    saveas(figure(1),'Cp.jpg');
    saveas(figure(2),'H.jpg');
    saveas(figure(3),'S.jpg');
    
   cd(current);
end

%function to calculate molecular weight
function Mo=Weight(Gas)

Weight=[1 12 14 16 32 0 40];
Gas1=['H' 'C' 'N' 'O' 'S' 'A' 'R'];
number=[1 2 3 4];

M=0;
GAS=char(Gas);
for i=1:length(GAS)
    for j=1:length(Gas1)
    if GAS(i)==Gas1(j)
        M(i)= Weight(j);
    end
    for j=1:length(number)
        if str2double(GAS(i))==number(j)
            M(i)=M(i-1)*(number(j)-1);
        end
    end
end
end

Mo=sum(M);
end

        

%function to calculate the Cp,H,S.
function [Cp,H,S]=coefficient(local_low_temp,local_average_temp,local_high_temp,La,Ha)
for i=1:local_high_temp-local_low_temp+1
    
    R=8.34;
    T=i+local_low_temp-1;
    %for lower temperature values
     if T<= local_average_temp
         Cp(i)=R*(La(1)+La(2)*T+La(3)*T^2+La(4)*T^3+La(5)*T^4);
         H(i)=R*T*(La(1)+(La(2)*T)/2+(La(3)*T^2)/3+(La(4)*T^3)/4+(La(5)*T^4)/5+La(6)/T);
         S(i)=R*(La(1)*log(T)+(La(2)*T)+((La(3)*T^2)/2)+((La(4)*T^3)/3)+((La(5)*T^4)/4)+(La(7)));
         
         %for higher temperature values
         
     else
         Cp(i)=R*(Ha(1)+Ha(2)*T+Ha(3)*T^2+Ha(4)*T^3+Ha(5)*T^4);
         H(i)=R*T*(Ha(1)+((Ha(2)*T)/2)+(Ha(3)*T^2)/3+(Ha(4)*T^3)/4+(Ha(5)*T^4)/5+(Ha(6)/T));
         S(i)=R*(Ha(1)*log(T)+(Ha(2)*T)+(Ha(3)*T^2)/2+(Ha(4)*T^3)/3+(Ha(5)*T^4)/4+(Ha(7)));
         
     end
end
end

The fist step in the code clears all the previously stored data on the command window.

The ‘fopen’ command opens the ‘THERMO.dat’ file and ‘r’ here indicated the ‘read only’ command. We use ‘fgetl’ command to read the data file line by line. The first line of the file is omitted and the next line is stores in a variable ‘line’ and the line is split using ‘strsplit’ command and stored in a variable ‘a’. Different temperature values are assigned to read the 53 gases mentioned in the data file we use for loop then we further read the lines in the file using fgetl command.

When all the global and local temperatures are read we call functions which are written to calculate molecular weight, specific heat(Cp),enthalpy(H),Entropy(s).

Calculating the value of Cp,H & S for local temperature range. Initial values of Cp, H & S are defined as zero, Plotting the graphs & saving them in the folder. It is standard procedure to store in file in specific location, by using many commands (pwd, mkdir, cd, saveas) written in this program.

We are using formulae to calculate Cp, H & S. We are using for loop to calculate each value at local temperature range. We are also using if & else command to use low & high temperature coefficient as per average temperature. If Temperature is less than average temperature then use low temperature co-efficient & If Temperature is more than average temperature then use hign temperature co-efficient

Molecular weight is calculated in a different function which is later called in the main function.